Dyk och Sjöentreprenad

Dyk & Sjöentreprenad i Uppsala AB is a Swedish specialist construction company focused on marine and underwater works. Established in 2000 and based in Uppsala, the company operates within the “rental of construction and civil engineering machinery with operators / other specialised construction” segment, providing equipment, barge capacity and operational crews for projects in and around water. The company acts as a marine subcontractor on subsea power cable projects, where it undertakes the physical installation and subsea handling of cables. In work for grid owner Ellevio in the Gothenburg archipelago, Dyk & Sjöentreprenad was responsible for installing 24 kV subsea power cables between Billdal and the island of Donsö under a turnkey contract led by Kraftringen Service. For this project, it transported three pontoons from its home base in Uppsala and configured them around an 11 x 7.5 metre barge with a 70‑tonne bearing capacity. During installation the barge was towed by a tug at 0.5–1 knots, laying 1,000‑metre cable drums on the seabed in 40–60 minutes and shuttling to shore-based facilities to reload drums. Beyond lay operations, Dyk & Sjöentreprenad provides subsea inspection and protection of installed assets. Its diver-led work on the Gothenburg project included swimming the cable route, visually confirming position, checking for contact with sharp stones or edges, manually repositioning cable where needed and applying closable protective tubes at sensitive points. These inspections were carried out at depths around 17 metres, with individual dives limited by safe bottom times, and generated video documentation to support future fault-finding and maintenance.